The present invention relates to a BMC processing circuit, a USB power delivery controller, BMC reception method and program, and relates to, for example, a stable Biphase Mark Code (BMC) reception processing technique with low power consumption.
The USB Power Delivery standard is one for controlling power supply via a USB cable. The USB Power Delivery standard defines that a power supply device (Source) and a power consumption device (Sink) may carry out negotiations regarding power supply by performing information communication using the BMC (BIPHASE MARK CODE) method.
The BMC method is an information transmission method that has been widely used, especially in the field of transmission of audio signals.
For example, the specification of US Patent Application Publication No. 2011/0261969 discloses a method in which a transmission apparatus and a reception apparatus negotiate a synchronization timing using the BMC method according to the SPDIF, ES3 (Audio Engineering Society3) format. Specifically, the reception apparatus determines the synchronization timing to be one of “0.5T”, “1T”, and “1.5T” according to whether a preamble of a reception packet is “B” (11101000 or 00010111), “M” (11100010 or 00011101), or “W” (11100100 or 00011011).
Further, in the method disclosed in the specification of US Patent Application Publication No. 2011/0261969, the reception apparatus detects a transfer bit rate and a bit boundary by measuring two high periods and two low periods of a reception signal in the preamble of the reception packet (see FIGS. 4A and 4B).